Clothing for a machine for manufacturing a web material

ABSTRACT

A fabric for a machine for producing web material, in particular paper, cardboard, tissue, film, a nonwoven product or a composite product, has a base fabric and at least two pattern components. The pattern components are applied to the base fabric. A cross-sectional shape of the first pattern component and a cross-sectional shape of the at least one further pattern component are different.

The invention proceeds from a clothing for a machine for manufacturing aweb material, such as, for example, paper, cardboard, tissue, film, anon-woven product, or a composite product, according to the preamble ofclaim 1.

A clothing of this type which may be employed as a forming wire in apaper machine, for example, is known from EP 1 690 981 A1. In this knownpaper machine clothing, a pattern from polymer material is applied in arotary printing method by means of a rotary screen to a carrierstructure which is configured as a woven fabric, for example. Thepattern in substantially any arbitrary design may be applied to thewoven carrier fabric, so as to generate on one side of the paper machineclothing thus manufactured a surface structure which during papermanufacturing is reproduced having a corresponding topography in themanufactured paper.

A method for applying a pattern to a paper machine clothing in which apolymer material in an extrusion operation is dispensed from anextrusion head and thus applied to the surface of a carrier structurewhich may be of a woven-fabric type, for example, is known from EP 1 690982 A1. The extrusion head may be moved arbitrarily above the surface ofthe carrier structure.

Furthermore, a clothing for a paper machine, in which a basic structureis printed multiple times with a polymer structure, wherein a firstpolymer layer has a grid-type structure and a second polymer layerlargely occupies the clearances in the grid-type first layer and therebypartially superimposes the first layer, is known from US2008/0991701A,for example. The manufacture of structures of this type here is achievedby applying a polymer to the entire area of the surface of the basicstructure, masking, radiating with light of a specific wavelength, and,on account thereof, curing the parts which are not masked, andsubsequently removing the non-cured polymer proportions.

A woven paper machine fabric for perfused air drying, which has athree-dimensional woven pattern which has a structure which has heightdifferences in the Z-direction of 0.2 mm or more, is known from U.S.Pat. No. 7,624,765B. The clothing has decorative elements which aresurrounded by accentuation areas, the decorative elements beingsurrounded by the three-dimensional woven pattern of the clothing andhaving a height lesser than the structure of the woven pattern. Thewoven pattern represents a structured background surface which is theprevailing contact area of the clothing with the paper web.

It is disadvantageous in the known clothings that the patterns which aregeneratable in this manner indeed may be fit for their decorativepurpose, for example by offering an aesthetic impression in the finishedproduct, for example, but that the physical properties of the clothingand of the product are incapable of being sufficiently influenced byonly one pattern component. It is thus desirable for variously shapedpatterns to be manufactured, for example, which fulfill differentfunctions. In many cases, combinations of patterns may indeed begenerated by way of the above-mentioned methods, the patterns howeverbeing all manufactured in the same way and the applied patterns thushaving identical cross-sectional shapes in all components, on account ofthe application method which is always identical. It is thus impossiblefor individual pattern components having different cross sections to beconfigured, such that it is likewise impossible for different patterncomponents for various tasks to be selectively configured in theclothing.

If and when various patterns are generated as a result of a specificdesign of the basic structure by way of a woven pattern and subsequentprinting using a polymer, the method is characterized by high complexityand thus also high costs.

It is thus an object of the present invention to state clothing which isreadily manufacturable and which has pattern components that permit thephysical and aesthetic properties of the clothing to be selectivelyinfluenced.

The object is achieved by the characterizing features of claim 1 incombination with the generic features.

It is provided here according to the invention that a cross-sectionalshape of a first pattern component and a cross-sectional shape of atleast one further pattern component are different from one another. Onaccount thereof, aesthetic motifs, for example, may be highlighted in anintense and sharp manner and may be surrounded by a background which hasbeen drawn so as to be softer and which is less prominent. Coarsepatterns for physically modeling de-watering parameters may be combinedwith fine patterns for designing a visually and haptically appealingsurface of the final product. The physical and aesthetic properties ofthe individual pattern components may thus be selectively modified andadjusted in a mutually independent manner, so as to emboss patterns ofvariable intensity in the finished product and so as to thus also modelthe physical and aesthetic properties of the finished product. It isfurthermore possible for the properties of the clothing in terms oftheir behavior during manufacturing of the fibrous web to be modeled andon account thereof for dynamic processes to be supported.

Further advantageous aspects and refinements of the invention arederived from the dependent claims.

According to one preferred embodiment of the invention it may beprovided that the cross-sectional shape of the pattern components isangular, in particular rectangular or square, or rounded, in particularat least segment-shaped or oval. On account thereof, structures whichare optionally less or more intensely prominent and which facilitate ininfluencing the aesthetic and physical properties may be generated inthe fibrous web.

An overall shape of the pattern components may be selected from drops,beads, lines, grid structures, contiguous or non-contiguous elements.

It may be advantageously provided that the pattern components are inmutual contact, mutually intersect, or are mutually isolated, dependingon the requirement profile.

It may be advantageously provided that the first pattern component iscomposed of a first material, and the at least one second patterncomponent is composed of a second material, wherein the first and thesecond material may be identical or different from one another. If andwhen various requirements are set for the pattern components, it may beadvantageous for one of the materials to be harder or softer, moreresistant to abrasion, smoother or coarser than the other material.

The material of the pattern components may preferably contain or becomposed of: amide, ester, silicone, urethane.

According to preferred aspects of the invention, sizing of the patterncomponents may be at a height of 0 to 10 mm above the basic structure,at a width of 0.1 to 10 mm, and at a length of 0.1 mm to indefinite.

Sizing of the pattern components may be particularly preferablyidentical or variable. There are thus no limits applicable to thediversity of patterns and the precise adjustment of the desired physicalparameters, in particular the desired dynamic parameters, of theclothing and to the arbitrary design of the final product.

Application of the pattern components to the basic structure may beperformed unilaterally or bilaterally, depending on intended use. Acombination with further components may likewise be performed, forexample in order to manufacture a pressing felt once printing of thebasic structure has been completed.

Application of the pattern components may be readily performed byapplication methods which are known per se, such as extruding, rollercoating, spraying, squeegee coating, or screen printing.

According to advantageous design embodiments of the invention, the basicstructure may be present as a woven fabric, a cross-laid structure, awarp-knitted fabric, a helical screen, a helically coiled structure, oras films, as a joinable planar structure, or as an endless belt.

The invention will be described in more detail in the following, by wayof example, with reference to the figures and without limiting thegeneral scope thereof. In the figures:

FIG. 1 shows a very schematic plan view of a clothing according to theinvention, and

FIG. 2 shows a very schematic cross-sectional view of a clothingconfigured according to the invention.

A plan view of a clothing 1, which is in particular suitable for use ina machine for manufacturing a fibrous web, such as a paper, cardboard,tissue, or film machine, and in a machine for manufacturing a non-wovenproduct or a composite product, is shown in a very schematic view inFIG. 1. A clothing 1 of this type is shown in a very schematic sectionalview in FIG. 2.

A plurality of clothings 1 which depending on their position fulfillvarious tasks are currently provided in such a machine. For instance, aclothing 1 in the forming section serves as a forming wire and thus forinitially de-watering the fibrous suspension which has been sprayed ontothe forming wire or has been injected between two forming wires in adouble-wire former, and for orienting the fibers in the nascent fibrousweb. Clothings 1 are provided as pressing felts for further de-wateringin the downstream pressing section, which clothings 1 should have a highabsorptive capacity for water, good resilience, smooth contact surfacesto the fibrous web, and a low tendency toward rewetting. The clothing 1in the drying section is often configured as a drying wire in the shapeof a helical structure and, on account thereof, is distinguished by ahigh resistance to temperature at high permeability to air.

Clothings 1 also often serve for incorporating a decorative pattern inthe fibrous web, this representing the current standard in the field ofhygiene tissues in particular. The patterns here have both aestheticfeatures as well as features which influence the properties of the paperweb, such as the grip of the surface, the thickness of the layers, etc.

The individual features here are often conceived such that a decorativeand often also personalized pattern is desirable, but that the latter isnot able to fulfill the requirements which are set for the physicalproperties of the fibrous web. It has thus been necessary to date forthe clothing 1 to be subjected to at least two separate operationalsteps in order for at least two patterns to be manufactured in or on therespective clothing. For example, as mentioned at the outset, ispossible for a three-dimensional structure to be generated whenmanufacturing a basic structure 2 of the clothing 1, and for thisstructure to be then superimposed by a pattern which is printed on atleast one surface of the clothing 1, for example. The structure of thebasic structure 2 here may be manufactured by established weavingpatterns, while the printed pattern is applied by a rotary screenprinting method, for example. Weaving of such basic structures 2 is inparticular a very complex process which moreover is very limited interms of its diversity of patterns. Due to the nature of weaving, ineach case only the machine direction, the machine cross direction, anddiagonals may be incorporated in the pattern; an arbitrary selection ofpatterns and a selective intervention in the property profile of theclothing 1 are thus not possible.

Therefore, it is proposed according to the invention to provide thebasic structure 2 with at least two pattern components 3, 4, which havedifferent cross-sectional shapes and thus generate different effects interms of the aesthetic appearance and the physical property profile ofboth the clothing 1 as well as of the finished product.

Arbitrary planar structures, such as woven fabrics, cross-laid fabrics,warp-knitted fabrics, helical wires, helically coiled structures, andalso films are employable here as the basic structure 2. The basicstructure 2 may be present in a flat form, having the potential forjoining, or as an endless belt. Permeability to liquids and gasses is tobe selected with a view to the application purpose of the clothing 1.The basic structure 2 may subsequently be combined with additionalcomponents which are not illustrated in more detail in the figures, suchas layers of staple fibers, films, non-woven reinforcement structures,or coatings on one or both sides, as well as other components, forexample impregnations, which adapt the clothing 2 to the prevailingconditions.

A plurality of at least two pattern components 3, 4 are applied to thebasic structure 2 by arbitrary application methods such as extruding (inthe form of drops, lines, films, etc.), coating (by rollers, spraying,or squeegee coating), or screen printing. Application here may beperformed on one or on both sides of the basic structure 2.

The pattern components 3, 4 here may be composed of an identicalmaterial or of different materials. Individual types of polymers or elsea plurality of specifically selected groups/classes of polymers may beprovided. The selection of the materials may be performed bothmicroscopically as well as macroscopically, depending on therequirements in terms of stability, sizing, smoothness, coefficient offriction, elasticity, open surface, open volume, permeability to gas andliquid, or conveyability of gas and liquid, respectively, etc., of theindividual pattern components 3, 4.

Examples of suitable materials here include amides, esters, silicones,and urethanes, and arbitrary combinations thereof.

As can be seen from FIGS. 1 and 2, the two pattern components 3, 4 inthe exemplary embodiment are provided both with different shapes as wellas with different cross sections. The first pattern component 3 isconfigured in the form of elongate formations having an angular crosssection, while the second pattern component 4 is present in the form ofrotund formations having a cross-sectional shape which is rounded in asubstantially convex manner.

Generating these variously shaped pattern components 3, 4 may beperformed, for example, by extruding a comparatively hard and rapidlycuring polymer out of a suitably shaped nozzle for the first patterncomponent 3, and by applying a rather liquid polymer which thus bleedsmore intensely in a drop-wise manner out of a differently shaped nozzlefor the second pattern component 4.

In the exemplary embodiment illustrated, a fine and richly detailedbackground structure in the finished product is generated by the secondpattern component 4 by means of a low height above the basic structureand soft and rounded shapes. The background structure of the producthere is generated by mechanical influences, such as hydraulic pressureand the distribution of the fibers in the fibrous suspension, and laterin the finished product.

By contrast, the first pattern component 3 stands proud of the basicstructure 2 to a greater height and, on account thereof, may impart ahigher topography associated with higher functionality. Advantagesderived therefrom may be seen in particular in optimizing the drainageof liquid or the conveyance of liquid, respectively, during the dynamicformation of the final product. This higher and coarser structure mayconversely serve as a reinforcement of the basic structure 2. The basicstructure 2 thus supports the pattern component 3, while the lattermakes available to the clothing 1 a higher volume for liquid absorption.The latter is an important parameter when judging the dynamic propertiesof the clothing 1. Throughput rates for masses and gasses are goodexamples of the dynamic state which is capable of being influenced here,such as can be seen in the drying process by way of migration of liquidor evaporation, for example.

Further advantages of the more intense topography of the first patterncomponent 3 are to be seen in the product having the ability to bethree-dimensional. Depending on the specific application of the clothing1, in particular on the point in time at which embossing into thefibrous web takes place during the manufacturing thereof, the ability tobe three-dimensional may be semi-permanent (similar to an embossing) ordurable and thus be a feature of the finished fibrous web. The lattermay be performed in particular during the final finishing steps, such asdrying or curing of the final product.

A further advantageous aspect of the high topography of the firstpattern component 3 is to be seen in facilitating drawing-in of theclothing 1 into the fibrous web machine. On account of there being fewerbearing points present, and on account of the coefficient of friction ofthe bearing points being able to be reduced due to suitable selection ofthe material which forms the pattern component 3, it is easier and saferfor the personnel to draw-in the clothing 1 and to dismount the latter.

With reference to the dimensions of the pattern components 3, 4,reference is made to current orders of magnitude which may be in therange of 0 to 10 mm in terms of height above the clothing 1, of 0.1 to10 mm in width and of arbitrary length for the first pattern component 3in the illustrated exemplary embodiment.

The rotund shapes of the second pattern component 4 in the exemplaryembodiment may have similar dimensions with an identical or similarextent in all spatial directions.

It is conceivable and possible for further pattern components which arenot illustrated in more detail and have further cross-sectional shapeswhich are identical or different from one another and are from the sameor different polymers, having the same or different sizes, to be addedto the two pattern components 3, 4 which are illustrated in theexemplary embodiment.

The invention is not limited to the illustrated exemplary embodiments.Combinations of the features are particularly possible and conceivable.

1-11. (canceled)
 12. A clothing for a machine for manufacturing a web material, the clothing comprising: a basic structure; at least two pattern components applied to said basic structure, said pattern components including a first pattern component and at least one further pattern component, wherein a cross-sectional shape of said first pattern component and a cross-sectional shape of said at least one further pattern component are different from one another.
 13. The clothing according to claim 12, configured for manufacturing a web material of paper, cardboard, tissue, film, a non-woven-product, or a composite product.
 14. The clothing according to claim 12, wherein the cross-sectional shape of said first and further pattern components is angular or rounded.
 15. The clothing according to claim 14, wherein the angular shape is square or rounded and the rounded shape is at least segment-shaped or oval.
 16. The clothing according to claim 12, wherein an overall shape of said first and further pattern components is selected from the group consisting of drops, beads, lines, grid structures, contiguous or non-contiguous elements.
 17. The clothing according to claim 12, wherein said pattern components are arranged to be in mutual contact.
 18. The clothing according to claim 12, wherein said pattern components are arranged to be intersect one another.
 19. The clothing according to claim 12, wherein said pattern components are arranged to be isolated from one another.
 20. The clothing according to claim 12, wherein said first pattern component and said at least one further pattern component are formed of identical materials or of different materials.
 21. The clothing according to claim 20, wherein said first and further pattern components contain or are composed of a material selected from the group consisting of amide, ester, silicone, and urethane.
 22. The clothing according to claim 12, wherein dimensions of said first and further pattern components are at a height of 0 to 10 mm above said basic structure, at a width of 0.1 to 10 mm, and at a length of 0.1 mm to indefinite.
 23. The clothing according to claim 22, wherein the dimensions of said first and further pattern components are identical to one another.
 24. The clothing according to claim 22, wherein the dimensions of said first and further pattern components are different from one another.
 25. The clothing according to claim 12, wherein said first and further pattern components are applied unilaterally to one side of said basic structure.
 26. The clothing according to claim 12, wherein said first and further pattern components are applied bilaterally to both sides of said basic structure.
 27. The clothing according to claim 12, wherein said first and further pattern components have characteristics of having been formed by a process selected from the group consisting of extruding, roller coating, spraying, squeegee coating, and screen printing.
 28. The clothing according to claim 12, wherein said basic structure is a woven fabric, a cross-laid structure, a warp-knitted fabric, a helical screen, a helically coiled structure, in the form of films, a joinable planar structure, or an endless belt. 